ED” is like “Shoot ‘Em Up” for grown-ups. It’s silly but not too silly, armed with a well-scripted plot that stays on mission even when the action sequences color outside the lines. And what it lacks in originality, it makes up for in Helen Mirren with a gun, which should be a requirement of all movies from now on.

Retired CIA “analyst” Frank Moses (Bruce Willis) is bored out of his mind. He calls Sarah (Mary-Louise Parker) and complains that his most recent government check has yet to arrive (even though it has) just to have someone to talk to. Once a group of armed goons tries to kill Frank in the middle of the night, he goes to see Sarah for the first time, but when another group of goons shows up soon after, he takes her against her will to seek out fellow retired assassins Joe (Morgan Freeman), Marvin (John Malkovich) and Victoria (Helen Mirren) in order to pool their assets and determine why they’re being targeted for termination. Hot on their trail is ambitious CIA up-and-comer William Cooper (Karl Urban), who quickly realizes that his boss may have undersold Frank’s survival skills a tad.

Nothing here will reinvent the action wheel, but for a movie where nearly every actor is over 40 (Urban is the lone youngster, at 38), “RED” has a surprising amount of youthful exuberance, and is wise to sprinkle those moments throughout the movie rather than save them for the action sequences. Sure, Willis’ car exit during a big shootout is one for the ages, but Malkovich’s non-lethal introduction is just as memorable. Even better, the characters are pulling off these beyond-their-years feats while still acting their age, which is key to suspending disbelief even if you know within the first 20 minutes which characters will live to see the closing credits.

This is the best role Willis has had in years, and he makes the most of it, playing Frank like a Zen John McClane. Malkovich has the flashiest part as the unstable Marvin, but it works because the script is careful to make sure his instincts are good, rather than painting him as a paranoid loose cannon. Mirren is your typical British dame, but watching her wield a machine gun is worth the price of admission alone. Parker’s role is a bit thankless, but fortunately she doesn’t spend the movie flailing clumsily like Jamie Lee Curtis in “True Lies.” The supporting characters, however, do not leave much to be desired, especially Richard Dreyfuss as the defense contractor Alexander Dunning and Rebecca Pidgeon as Cooper’s boss. We get why David Mamet hires Pidgeon for his movies – she’s his wife. Why anyone else hires her is a mystery.

“RED,” much like “The Town,” won’t be anyone’s favorite movie, but so what? It’s well made, well acted (by the leads, anyway), and the shootouts are gobs of fun, plus it has, to paraphrase Mirren, a gooey interior that makes it good date movie material as well. All concerned clearly had a great time making this movie, and while that doesn’t always make for an equally enjoyable viewing experience, it does here.